Sensor Flush™ is an automatic sensor toilet flushing system that can retrofit most existing home tank style toilets. Sensor Flush™ has built-in sophisticated proximity sensors in the flush handle that lock onto objects and flushes automatically after the user is out of sight. With its 100% touch free technology, it efficiently reduces the chance of cross contamination of germs, providing greater convenient and a germ-free and hygienic bathroom environment. It fits any toilet tank that has flush handle mounted on the front or 45 degrees of the tank. The sensor unit can also be secured on top of all toilet tanks with supplied double-sided tape. Package comes with all installation tools including batteries. Batteries can last up to 3 years or 23,000 flushes.